Strand treatment

ABSTRACT

In vibratory bulking or crimping of textile strands, the twiststopping tendency of a vibratory crimping head is overcome by false-twisting in the vicinity of the locus of vibration and thereby, in effect, forwarding twist therethrough. The crimping step conveniently is preceded by a step of drawing the strands to increased length.

D United States Patent 1 1 1 3,729,914 McClure 1 May 1, 1973 s4 ST D T E T 3,377,673 4/1968 Stoller ..28/l.2

3,646,744 3/ 1972 Rusca ..57/34 [76] Inventor: Charles A. McClure, RD. 2, Mal- 19355 Primary Examiner-Wemer H. Schroeder 22 i June 8 1971 Attorney-McClure & Millman 1 pp 150,962 57 ABSTRACT In vibratory bulking or crimping of textile strands, the g Cl 57/157 157 twist-stopping tendency of a vibratory crimping head 1.2 is overcome by false-twisting in the vicinity of the [51] Int. Cl. ..D02g 1/00 locus of vibration and thereby, in effect, forwarding [58] Field of Search ..57/2.3, 34 HS, 77.3, twist therethrough. The crimping step conveniently is 57/157 R, 157 TS, 157 MS; 28/ l .2 preceded by a step of drawing the strands to increased length. [56] References Cited UNITED STATES PATENTS 17 Claims, 8 Drawing Figures Pate ntecl May 1, 1973 mwwme CHARLES A. MCLURE 2 Sheets-Sheet 2 V STRAND TREATMENT This invention relates to bulking or crimping of textile strands by vibration thereof, especially at ultrasonic rates, or at rates in the upper sonic range.

In addition to more conventional procedures for imparting bulky or crimped configuration to a textile strand, such as by passing it between intermeshing gears, into confining chambers, over sharp edges, and through air jets, it is also known to vibrate such a strand transversely for a like purpose. However, the results of attempted vibratory crimping have been less than satisfactory, because of processing difficulties and processing irregularities.

A primary object of the present invention is improved uniformity of vibratory crimping of textile strands.

Another object is improved twist maintenance in vibratory crimping of textile strands.

A further object is a continuousprocess of drawing and vibratory crimping of textile strands.

Other objects of this invention, together with means and methods of attaining the various objects will be apparent from the following description and the accompanying diagrams.

FIG. 1 is a block diagram of a process for treating textile strands including a step of vibratory crimping;

FIG. 2 is a more detailed, block diagram of strandtreating steps according to this invention, including vibratory crimping;

FIG. 3 is a schematic diagram of apparatus for practicing the process indicated in FIG. 1;

FIG. 4 is a schematic diagram of apparatus for practicing the steps indicated in FIG. 2; and

FIG. 5 is a fragmentary side elevation of a component of FIG. 4;

FIG. 6 is an end elevation of related apparatus components of preceding views;

FIG. 7 is a side elevation of the components of FIG.

FIG. 8 is a schematic diagram of apparatus similar to but modified somewhatfrom that of FIG. 4;

In general, the objects of the present invention are accomplished, in vibratory crimping of textile strands, by the steps of preheating a textilestrand for crimping, passing the strand under tension through a vibratory zone, and collecting the strand in crimped condition at reduced temperature and tension. More particularly, this invention comprises running a textilestrandhaving a given twisttherein ,through a vibratory zone, thereby imparting a crimped configuration thereto, andmaintaining the twist in the treated strand.

FIG. 1 indicates in block form a sequence of steps for a process comprising a strand-drawing step 3 and a subsequent vibratorycrimping step 7. Also indicated are a preconditioning step 1 preceding the drawing step, a conditioning step 5 intervening between the drawing and crimping steps, and a postconditioning step 9 following the crimping step. Whereas the various conditioning steps usually involve adjustment or control of such factors as humidity or moisture content, temperature, and tension, this invention also considers twist as a condition to be controlled.

FIG. 2 indicates in block form a detwisting step 6 in advance of vibratory crimping step 7 and a retwisting step 8 thereafter. Considered together, such steps constitute false-twisting in the vicinity of the vibratory crimping, as prescribed according to one formo invention and described further hereinafter.

FIG. 3 shows schematically the passage of a textile strand through the steps of FIG. 1. Strand 10 passes successively through preconditioning zone 11, a draw} ing zone shown as being made up of first godet and separator rolls 12, 12', draw pin 13, and second godet and separator rolls 14, 14', conditioning zone 15, vibratory crimping zone 17, postconditioning zone 19, and over windup roll 20 onto receiving bobbin 20'.

It will be understood that strand 10 may be furnished from a bobbin or other package (not shown) and alternatively may be withdrawn from a strand-formation zone. Strand-forming processes include extrusion through one or more spinnerets int-o multifilament form or splitting of extruded sheet film into narrow filamentlike strips, for example. The strand is forwarded suitably by conventional driving of the illustrated or other rolls, and illustration of drive means would be superfluous. Of course, second godet 14is driven at a sufficiently greater surface speed than first godet 12 so as toaccomplish the desired drawing of the strand to in creased length therebetween, as conveniently localized at snubbing pin 13. Windup roll 20, which is driven at a lower speed than the second godet, because the crimping step reduces the effective overall length of the strand, is conveniently of grooved type so as to traverse the strand while winding it onto the receiving bobbin.

This invention provides means and methods for overcoming the tendency of vibratory means to interfere with twist present in textile strands being treated. In conventional treatments such twist tends to accumulate at the upstream side of such means so as to increase the twist in the incoming or untreated strand and to decrease the twist in the outgoing strand downstream. Twist accumulation may result in snagging or breaking of the strands as well as uneven treatment. One embodiment of an arrangement to overcome such difficulty is shown in the next few views.

FIG. 4 shows an embodiment of apparatus useful according to the invention as in the preceding views, while certain components thereof appear (enlarged) in FIGS. 5, 6, and 7. Strand 10 passes in succession through detwisting roll 26, vibratory crimping head 27, and retwisting roll 28. The detwistingand retwisting rolls constitute, together with main drive belt23, intermediate roll 24 driven thereby, individual drive belt 25 to roll 26, and individual drive belt 29 to roll 28, a falsetwisting apparatus for the strand in the vicinity of the crimping head. Head 27 itself is driven transversely of the strand path by a transducer comprising piezoelectric crystal 30 (marked XTAL) and column31 interconnecting the crystal to the head. The crystal is driven by high-frequency a.c. generator 33 (marked GEN.) interconnected thereto by pair of wires 34.

The strand path is shown more clearly in FIGS. 5, 6, and 7. FIG. 5 shows vibratory crimping head 27 onan enlarged scale and viewed end-on to the path of strand 10 (shown sectioned transversely). Tapered slot 37 in the front side of the head communicates with asmall bore in which the strand is confined, with respect to the direction of vibration indicated by the double-headed arrow alongside column 31, and through which the strand passes in its longitudinal direction.

For the sake of clarity, strand is omitted from the end view of retwisting roll 28 in FIG. 6, but its path therethrough is clear from the side view thereof in FIG. 7. It will be noted also that the position of the roll in FIG. 6 is about thirty degrees of rotation past that shown in FIG. 7. Individual drive belt 29 is located about 'one end of the roll. The opposite end of the roll has bore 41 of large diameter extending axially therein and erupting to opposite sides in slot 42. A small axial bore (not visible) interconnecting endwise with the large bore midway of the roll erupts to the surface at one side only in narrow slot 44. Strand 10 traverses the small bore and then enters the large bore where it encounters idler pulley 47 mounted on transverse axle 48. After taking a turn about the pulley, the strand passes endwise out of the roll bore and onward as previously indicated.

In the practice of this invention, which is readily understood by reference to the foregoing description and diagrams, strand-crimping is accomplished as the strand under tension passes to and from the vibrating head. In the embodiment already described, detwisting and retwisting rolls flanking the head are rotated at a rate sufficient to false-twist the strand to a substantially zero-twist condition at the head, thereby precluding the head from acting as a cumulative twist-stop at its upstream edge; of course, the downstream edge stops the reinserted twist from running back upstream of the strand path. It will be understood that, although both rolls and the crimping head are shown axially aligned for simplicity of illustration, they may be offset to whatever extent may be desired for optimum crimping. The angle between the direction of vibration and the strand path may be varied also, an example thereof being shown in the next view.

FIG. 8 shows a modified embodiment in which transducer column 31 drives modified crimping head 27 at an angle of about 45 to the undeflected strand path. It will be understood that such angle can be made less or even more acute by appropriate modification of the apparatus components. The illustrated trapezoidal shape of head accommodates (or is accommodated by) detwisting roll 26' and retwisting roll 28' having their adjacent ends modified into conical form. In other respects the modified apparatus components are the same as or equivalent to the corresponding components (having unprimed reference characters) as shown in preceding views.

The strand furnished to whatever vibratory crimping apparatus is employed is otherwise appropriately conditioned also. It usually is advantageous to treat the strand at elevated temperature, the degree of heating being dependent upon the strand composition and being sufficient to render it amenable to crimping distortion but not so plastic as to fail to retain such distortion to a desired extent. If, as is preferred, the strand is being drawn to increased length immediately before the crimping, in a continuous process, it

preferably will be preheated in the preconditioning step for drawing. Then, in the intermediate conditioning step, the elevated temperature already attained may be substantially maintained with little or no addition of heat. Post-conditioning to cool the crimped strand to or near room temperature is preferred. If desired, a subsequent reheating and cooling may be employed to relax the crimped strand and relieve residual internal strains to a greater or lesser extent. I-Iumidity or moisture contentmay be controlled in one or more of the conditioning steps as appropriate to the strand composition. The strand is maintained under tension throughout the treatment until released to a much lower or mere winding level as soon as possible downstream of the crimping head, such tension being determinable from the relation between the windup speed of roll 20 on the one hand and, on the other hand, the speed of roll 28 or 28', rolls 58, 59 or roll 60 as the case may be.

The rate of strand travel usually is not critical because the speed of vibration is suitably high relative thereto. Thus, the strand may be fed to the crimping head at from several hundred to a thousand yards or meters per minute or even faster. The frequency of vibration preferably is in the low ultrasonic or high sonic range, such as from about 10 kHz to 1 MHz. The displacement or stroke of the crimping head is necessarily small, from several thousandths to several hundredths of an inch, or about one hundreth to one tenth centimeter. The power required is a function of the mass being vibrated, which accordingly should be kept as small as feasible, and powers approaching watts are suitable. Magnetostriction transducers may be substituted for the suggested piezoelectric type, if desired, depending upon technical considerations.

This invention provides a high-speed crimping or draw-crimping process for textile strands of almost any composition. The resulting crimp may be made of very fine texture by using a high ratio of vibration speed to speed of strand travel. The power requirements are modest, and it will be understood that a number of separate strands may be treated side-by-side by a single crimping head especially when twist accumulation is not a problem.

While embodiments have been illustrated and described by way of example, other modifications may be made, as by adding, combining, or subdividing parts or steps, while retaining some or all of the benefits and advantages of this invention, which itself is defined in the following claims.

The claimed invention is:

1. In vibratory crimping of textile strands, wherein a textile strand with a given twist therein is passed through a vibratory zone having a twist-stopping action, thereby imparting a crimped configuration thereto, the improvement comprising maintaining the twist in the treated strand, by false-twisting the strand in the vicinity of the locus of vibration and thereby counteracting the twist-stopping action in the vibratory zone.

2. Strand crimping according to claim 1, wherein the strand is false-twisted to have substantially zero twist in the vibratory zone.

3. Strand crimping according to claim 1, wherein a plurality of strands are so treated simultaneously sideby-side in the same vibratory zone.

4. In-vibratory crimping of textile strands wherein at least one textile strand having twist therein is passed through a vibratory zone and is crimped by vibration therein, the improvement comprising detwisting the strand immediately in advance of the zone and thereafter retwisting it, whereby the resulting crimp is rendered more uniform.

5. Strand crimping according to claim 4, including the step of preheating the strand in advance of the vibratory zone to an elevated temperature at which it is amenable to crimping distortion.

6. Strand crimping according to claim 5, including the step of maintaining the strand at such elevated temperature in the vibratory zone.

7. Strand crimping according to claim 5, including the step of cooling the crimped strand upon its exit from the vibratory zone.

8. Apparatus for vibratory crimping of textile strands having twist therein, comprising a vibrating head to which a textile strand is juxtaposed for crimping, and adjacent means for rotating the strand about its axis in a direction opposite to the twist and thereby enabling the strand to undergo any desired reduction in twist before being juxtaposed to the head.

9. Strand-crimping apparatus according to claim 8, wherein the means for rotating the strand includes a strand-detwisting roll adjacent the head.

10. Strand-crimping appparatus according to claim 9, wherein the means for rotating the strand includes also a strand-retwisting roll adjacent the head, the respective rolls flanking the head.

11. Appparatus for vibratory crimping of textile strands, comprising a vibratory head to which a textile strand is juxtaposed for crimping, means for effecting vibratory displacement of the head to and fro along a given axis, means for passing a textile strand along an undeflected path oriented obliquely relative to the head and intercepting the axis of displacement o fthje 12. Strand-crimping apparatus according to claim 11, wherein the means for rotating the strand includes a pair of rolls flanking the vibratory head, and means for rotating the rolls in the same direction whereupon one roll is adapted to detwist the strand and the other roll to retwist it.

l3. Strand-crimping apparatus according to claim 11, wherein the means for effecting vibratory displacement has a strand-receiving slot therein oriented substantially parallel to the undeflected strand path.

14. Strand-crimping apparatus according to claim 8, including means for forwarding the strand continuously past the vibratory head.

15. Strand-crimping apparatus according to claim 14, including means for drawing the strand to increased length in advance of the vibratory head.

16. Apparatus for drawing and crimping textile strands, comprising means for forwarding a textile strand, means for drawing the strand to increased length while being forwarded, vibratory strand-crimping means located downstream of the drawing means, and detwisting means located between the drawing means and the crimping means.

17. Strand-crimping apparatus according to claim 16, including also strand-retwisting means located downstream of the vibratory head. 

1. In vibratory crimping of textile strands, wherein a textile strand with a given twist therein is passed through a vibratory zone having a twist-stopping action, thereby imparting a crimped configuration thereto, the improvement comprising maintaining the twist in the treated strand, by false-twisting the strand in the vicinity of the locus of vibration and thereby counteracting the twist-stopping action in the vibratory zone.
 2. Strand crimping according to claim 1, wherein the strand is false-twisted to have substantially zero twist in the vibratory zone.
 3. Strand crimping according to claim 1, wherein a plurality of strands are so treated simultaneously side-by-side in the same vibratory zone.
 4. In vibratory crimping of textile strands wherein at least one textile strand having twist therein is passed through a vibratory zone and is crimped by vibration therein, the improvement comprising detwisting the strand immediately in advance of the zone and thereafter retwisting it, whereby the resulting crimp is rendered more uniform.
 5. Strand crimping according to claim 4, including the step of preheating the strand in advance of the vibratory zone to an elevated temperature at which it is amenable to crimping distortion.
 6. Strand crimping according to claim 5, including the step of maintaining the strand at such elevated temperature in the vibratory zone.
 7. Strand crimping according to claim 5, including the step of cooling the crimped strand upon its exit from the vibratory zone.
 8. Apparatus for vibratory crimping of textile strands having twist therein, comprising a vibrating head to which a textile strand is juxtaposed for crimping, and adjacent means for rotating the strand about its axis in a direction opposite to the twist and thereby enabling the strand to undergo any desired reduction in twist before being juxtaposed to the head.
 9. Strand-crimping apparatus according to claim 8, wherein the means for rotating the strand includes a strand-detwisting roll adjacent the head.
 10. Strand-crimping appparatus according to claim 9, wherein the means for rotating the strand includes also a strand-retwisting roll adjacent the head, the respective rolls flanking the head.
 11. Appparatus for vibratory crimping of textile strands, comprising a vibratory head to which a textile strand is juxtaposed for crimping, means for effecting vibratory displacement of the head to and fro along a given axis, means for passing a textile strand along an undeflected path oriented obliquely relative to the head and intercepting the axis of displacement of the head, and including adjacent means for rotating the strand about its own axis along the undeflected path.
 12. Strand-crimping apparatus according to claim 11, wherein the means for rotating the strand includes a pair of rolls flanking the vibratory head, and means for rotating the rolls in the same direction whereupon one roll is adapted to dEtwist the strand and the other roll to retwist it.
 13. Strand-crimping apparatus according to claim 11, wherein the means for effecting vibratory displacement has a strand-receiving slot therein oriented substantially parallel to the undeflected strand path.
 14. Strand-crimping apparatus according to claim 8, including means for forwarding the strand continuously past the vibratory head.
 15. Strand-crimping apparatus according to claim 14, including means for drawing the strand to increased length in advance of the vibratory head.
 16. Apparatus for drawing and crimping textile strands, comprising means for forwarding a textile strand, means for drawing the strand to increased length while being forwarded, vibratory strand-crimping means located downstream of the drawing means, and detwisting means located between the drawing means and the crimping means.
 17. Strand-crimping apparatus according to claim 16, including also strand-retwisting means located downstream of the vibratory head. 